In connection with the care and treatment of wounds herein, the term "wound" is meant to include chronic wounds such as pressure ulcers (Stage I-IV) and leg ulcers, acute wounds such as surgical wounds (e.g., post operative wounds), traumatic wounds such as minor abrasions and lacerations, burns (first and second degree), punctures, Moh's surgery, dermatological excisions, and the like. A critical aspect of wound care is the consideration of the requirements of the epithelium, i.e., that area of new cell growth over the wound which is formed during the healing process, so that healing is facilitated. Another consideration in wound care is the needs of the surrounding unwounded skin.
Since it is recognized that healing of the wound occurs as the epithelium migrates by growth generally from the periphery inward, care is taken not to damage unnecessarily or to irritate this new area of growth or existing compromised tissue. Frequently, with prior art dressings, problems can occur when dressings are left on a wound for too long a period of time and during dressing changes. For example, dressings can adhere to the epithelium, and granulation tissue and new cell growth can become intertwined within the matrix of the dressings. In these instances, there is a risk that removal of the dressing will damage the sensitive tissue and new growth thereby causing a regression in the progress of wound healing.
Accordingly, another critical consideration in wound care is the frequency of dressing changes. It may be desirable to change dressings frequently when the wound is emitting a large volume of exudate, and less frequently when the wound is emitting less exudate. Nevertheless, each time the dressing is changed, there is a risk that the sensitive tissue and new growth will be unnecessarily damaged. Additionally, positive growth factors in wound fluid might be unnecessarily removed from the wound bed thereby preventing their positive effects. Therefore, it is important to change the dressings when appropriate but not so often as to unnecessarily damage the sensitive tissue and new growth, or to remove the positive growth factors unnecessarily.
Unfortunately, most prior art dressings rely on the caretaker or the patient to decide if a dressing should be changed. In particular in the case of a non-health care professional or the patient alone, it can be difficult to know when a dressing should be changed. For example, one type of wound treatment presently used, in particular for leg ulcers, comprises the application of gauze to the ulcer and the utilization of a compression wrap to secure the gauze to the ulcer. The caretaker essentially must simply guess when it is appropriate to change the dressing. If the dressing is changed too frequently, the underlying tissue can be damaged and part of the useful life of the dressing is wasted. However, if the gauze is left on for too long a period of time, wound exudate can begin to overly hydrate and macerate the patient's surrounding skin.
Some dressings have been made which provide means for monitoring the condition of the underlying skin or wound. For example, a dressing is disclosed in U.S. Pat. No. 5,181,905. This dressing is preferably provided with an electrical-mechanical indicator means capable of sensing the condition of the underlying skin or wound. This indicator is a series of temperature sensitive, color responsive encapsulated liquid crystals.
Other bandages with indicators exist as well such as the bandage shown in U.S. Pat. No. 3,675,654. This bandage includes an absorbent pad disposed on a translucent backing sheet of water impervious material. A moisture-actuated indicating agent is positioned between the pad and the backing sheet. The indicating agent is a small amount of water-soluble dye. When the absorbent pad and the indicating agent become wet in use, the resulting solution between the pad and the backing sheet is visible through the backing sheet to provide an indication of wetness. However, an indication of wetness alone is not necessarily enough to indicate that the bandage should be changed. In fact, if the bandage were changed every time any wetness occurred, the bandage may be being changed too frequently and there is the risk that the sensitive tissue and new cell growth are being damaged each time.
Markings have also been provided on bandages, for example, to indicate the appropriate direction for removal of the bandage from a patient's skin to minimize damage to the underlying healing wound (see, e.g., U.S. Pat. No. 4,334,530), to monitor the size reduction of the wound (see, e.g., U.S. Pat. No. 5,000,172) and to mark the optimum spot for applying pressure to stop bleeding (see, e.g., U.S. Pat. No. 5,310,402).
Nevertheless, considering the various types of wounds, the numerous dressings that are available, and the various stages of healing, there remains a need for a dressing that minimizes premature dressing changes, particularly by the non-health care professional, and thereby optimizes the life of the bandage and yet works to prevent damage to surrounding skin, tissue and new cell growth by frequent dressing changes.